Then there's no point. Ford's I6T beats Holdens V8 quite easily. Made the XR8 redundant to anyone that wasn't both a Ford and V8 die hard. Holden's best V8 sellers are the SS, SSV (sedan, ute and wagon). If they bring out a turbo 6 to compete with the Ford turbo 6, then it would have to end up beating Holden's V8 as well. A market they do not want to lose.